The worm turns

A MOLECULAR trick that prevents a parasitic worm being digested in the gut has been uncovered. Surprisingly, the finding could lead to new treatments for high blood pressure and cancer.

Michael James and his colleagues at the University of Alberta in Edmonton studied the worm Ascaris lumbricoides, which infects about a billion people worldwide. They discovered how pepsin inhibitor-3, a protective protein secreted by the worm stifles pepsinan enzyme that would otherwise destroy it (Nature Structural Biology, vol 7, p 653). "It effectively cloaks the pepsin so its active site is virtually inaccessible," says James.

The team hopes that altered forms of the inhibitor could block enzymes similar to pepsin that have been linked with high blood pressure and the spread of cancer.

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